Understanding the microscopic origin of the magnetic interactions in CoNb₂O₆
- Motivated by the on-going discussion on the nature of magnetism in the quantum Ising chain CoNb2O6, we present a first-principles-based analysis of its exchange interactions by applying an \textit{ab initio} approach with additional modelling that accounts for various drawbacks of a purely density functional theory ansatz. With this method we are able to extract and understand the origin of the magnetic couplings under inclusion of all symmetry-allowed terms, and to resolve the conflicting model descriptions in CoNb2O6. We find that the twisted Kitaev chain and the transverse-field ferromagnetic Ising chain views are mutually compatible, although additional off-diagonal exchanges are necessary to provide a complete picture. We show that the dominant exchange interaction is a ligand-centered exchange process - involving the eg electrons -, which is rendered anisotropic by the low-symmetry crystal fields environments in CoNb2O6, giving rise to the dominant Ising exchange, while the smaller bond-dependent anisotropies are found to originate from d−d kinetic exchange processes involving the t2g electrons. We demonstrate the validity of our approach by comparing the predictions of the obtained low-energy model to measured THz and inelastic neutron scattering spectra.
Author: | Amanda A. KoniecznaORCiD, David Andreas Songzi KaibORCiDGND, Stephen M. WinterORCiD, Roser ValentíORCiDGND |
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URN: | urn:nbn:de:hebis:30:3-860131 |
URL: | https://arxiv.org/abs/2406.17854v1 |
DOI: | https://doi.org/10.48550/ARXIV.2406.17854 |
ArXiv Id: | http://arxiv.org/abs/2406.17854 |
Parent Title (German): | arXiv |
Publisher: | arXiv |
Document Type: | Preprint |
Language: | English |
Date of Publication (online): | 2024/06/25 |
Date of first Publication: | 2024/06/25 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/07/01 |
Issue: | https://arxiv.org/abs/2406.17854v1 |
Edition: | Version 1 |
Page Number: | 14 |
Institutes: | Physik / Physik |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |